This proposal requests support for renewal of the long-standing pre-and postdoctoral Training in Virology T32 at the University of Pennsylvania. Over the past 20 years hundreds of PhD and postdoctoral trainees have been mentored in viral research by our faculty. This training program currently includes 21 laboratories directed by well- established and well-funded investigators at the University of Pennsylvania, the Wistar Institute, and CHOP selected from over 40 NIH-funded laboratories studying viruses on the contiguous campus that houses these institutions. Addition of new trainers including George Shaw, Matt Weitzman, Sara Cherry, Kyong-Mi Chang and Carolina Lopez has strengthened an already outstanding cadre of mentors. The primary goal of the Virology Program is to identify, mentor and develop the careers of future leaders dedicated to biomedical research in the field of virology. Toward this end, we crafted a well-organized training program that includes outstanding mentors, an exceptional pool of candidates, outstanding institutional support and facilities, and training activities comprised of formal coursework in virology and immunology, an invited scientist speaker series, a student and postdoc research in progress seminar series, and a career development/Alumni day. New initiatives include Individualized Development Plans for all trainees, a UPenn Virology LinkedIn group to track and network with former trainees, a well described set of metrics to gauge success, and fellowship preparation instruction for incoming PhD students. Penn continues to provide direct and tangible institutional commitment to training in the biomedical sciences by supporting predoctoral trainees for their first 21 months of graduate school and funding the Biomedical Postdoctoral Programs office. Over the past five year funding period, this Virology T32 directly supported a total of 27 trainees including 19 predoctoral trainees (12 PhD, 6 MD/PhD, 1 VMD/PhD, 9 men, 10 women, 1 under-represented minority) and eight postdoctoral fellows (2 men, 6 women, 1 under-represented minority). These 27 trainees worked in the labs of 15 different trainers. Success of this program is exemplified by the former trainees who developed into independent scientists studying viral biology including Carolyn Coyne, Blossom Damnia, Anthony Nicola, Andy Pekosz, and Matt Weitzman among others. In following the review recommendations, we propose supporting four pre-doctoral and three postdoctoral trainees per year.